TrueFix

Production-grade FIX engine for Rust.

• ✓ FIX 4.0–FIX 5.0 SP2, FIXT 1.1, and FIX Latest
• ✓ Initiator and acceptor, including multi-session and dynamic acceptors
• ✓ QuickFIX/J-compatible .cfg configuration
• ✓ Persistent message stores and structured logs
• ✓ TLS and mTLS with rustls
• ✓ Async Tokio runtime
• ✓ 483/483 black-box FIX conformance scenario runs passing

cargo add truefix@0.1.10

use std::sync::Arc;
use truefix::config::SessionSettings;
use truefix::{Application, Engine};

let settings = SessionSettings::parse(&std::fs::read_to_string("session.cfg")?)?;
let engine = Engine::start(&settings, Arc::new(MyApp)).await?;

MyApp implements the async Application callbacks for session and application messages. Everything else—sessions, networking, TLS, persistence, schedules, reconnect, and dictionaries—can be selected from configuration.

Why TrueFix?

TrueFix is for teams that want Rust's memory safety and async ecosystem without giving up the operational features expected from an established FIX engine.

Capability	TrueFix	QuickFIX/J	FerrumFIX
Rust native	Yes	No (Java/JVM)	Yes
Initiator + acceptor	Built in	Built in	Library primitives
QuickFIX/J .cfg files	Compatible	Reference format	No
Persistent stores	Memory, file, SQL, MSSQL, redb, MongoDB, custom	Built in	Application-provided
TLS / mTLS	Built in	Built in	Integration-dependent
Async Tokio integration	Built in	No	Runtime-agnostic
Black-box conformance gate	483/483 scenario runs	Acceptance-tested	Project-specific tests

This is a project-positioning comparison, not a claim of certification or complete feature identity. See QuickFIX/J parity for scope and evidence.

Quick start

Create session.cfg:

[DEFAULT]
ConnectionType=initiator
ReconnectInterval=5
HeartBtInt=30
FileStorePath=.truefix/store
FileLogPath=.truefix/log
UseDataDictionary=Y
DataDictionary=FIX.4.4

[SESSION]
BeginString=FIX.4.4
SenderCompID=CLIENT
TargetCompID=BROKER
SocketConnectHost=127.0.0.1
SocketConnectPort=9876

Implement the application callbacks and run the engine:

use std::sync::Arc;

use truefix::config::SessionSettings;
use truefix::{Application, Engine, SessionId};

struct MyApp;

#[async_trait::async_trait]
impl Application for MyApp {
    async fn on_logon(&self, session: &SessionId) {
        println!("logged on: {session}");
    }
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let cfg = std::fs::read_to_string("session.cfg")?;
    let settings = SessionSettings::parse(&cfg)?;
    let engine = Engine::start(&settings, Arc::new(MyApp)).await?;

    tokio::signal::ctrl_c().await?;
    engine.shutdown();
    Ok(())
}

See Getting started and the runnable executor, banzai, ordermatch, and multi_acceptor examples.

What is included?

• Strict SOH codec with BodyLength/CheckSum validation and typed FIX messages
• Session sequencing, heartbeat, resend, gap-fill, reset, scheduling, and recovery
• Runtime data dictionaries plus generated typed messages, fields, and repeating groups
• Multi-endpoint reconnect, proxy support, socket controls, TLS/mTLS, and bounded backpressure
• Memory, file, cached-file, SQL, MSSQL, redb, MongoDB, and custom store/log backends
• Metrics-facade integration and structured tracing
• FAST and SBE codec crates alongside the tag-value FIX engine

Workspace crates

Every published crate can be depended on independently. Use truefix for a complete FIX engine; choose a lower-level crate when you only need one layer. Broker clients are standalone SDKs and do not require the FIX engine.

Crate	Independently usable	Purpose and supported scope
truefix	Yes — recommended FIX entry point	Facade, application callbacks, .cfg-driven engine startup, and re-exports of FIX layers
truefix-core	Yes	Runtime-neutral FIX message model, SOH codec, framing, typed fields, groups, and dispatch
truefix-dict	Yes	Runtime dictionaries, validation, QuickFIX XML/FIX Orchestra conversion, and typed code generation
truefix-session	Yes, with caller-supplied I/O	Sans-I/O session state machine: logon, sequencing, resend, heartbeat, schedules, and callbacks
truefix-transport	Yes	Tokio initiator/acceptor runtime, TCP/TLS, proxies, multi-session routing, backpressure, and shutdown
truefix-config	Yes	QuickFIX-compatible .cfg parsing, inheritance, validation, schedules, TLS, proxy, store, and log settings
truefix-store	Yes	Memory, file, cached-file, noop, SQL, MSSQL, redb, MongoDB, and custom message stores
truefix-log	Yes	Screen, file, tracing, composite, SQL, MSSQL, redb, MongoDB, and custom FIX logs
truefix-binary	Yes	FAST and SBE codecs over the shared message model; not a multicast/session transport
truefix-at	Yes, for maintainers/tests	Black-box FIX conformance harness; application runtime dependency is normally unnecessary
truefix-futu-client	Yes	Futu OpenD protobuf client, request correlation, reconnect, quote/trade requests, and pushes
truefix-twsapi-client	Yes	Interactive Brokers TWS/IB Gateway wire client for market data, accounts, orders, contracts, and events
truefix-okx-client	Yes	OKX V5 typed REST plus public/private/business WebSocket APIs and 264-operation inventory
truefix-ig-client	Yes	IG REST and Lightstreamer client, v2/v3 authentication, positions, working orders, and live updates

Latest release

TrueFix 0.1.10 aligns every published workspace crate under one release version, including the standalone broker and exchange clients.

Documentation

• Getting started — prerequisites and runnable workflows
• Architecture — workspace layers, dictionaries, and extension points
• Conformance — the 483-scenario release gate and validation commands
• QuickFIX/J parity — compatibility scope and historical parity work
• Security audits — safety policy and audit trail
• Full documentation index

Development

cargo fmt --all --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace
cargo test -p truefix-at --test conformance

TrueFix uses Rust edition 2024 and has an MSRV of Rust 1.96. unsafe is forbidden workspace-wide; critical non-test paths deny panic-prone operations through lint policy.

License

Licensed under either Apache License 2.0 or MIT, at your option.

TrueFix is independently implemented from the FIX specification. QuickFIX/J and QuickFIX/Go were used to study architecture and protocol behavior; their source and private data files were not copied or translated.